A Senate subcommittee yesterday opened hearings that could lead to the first action ever taken in Congress on the touchy subject of affirmative action.

"What is remarkable is that the affirmative action concept -- one with so many important implications for what our nation is all about -- should have begun to take root within our system almost totally in the absence of legislative sanction," said Sen. Orrin G. Hatch, who chaired the hearing to examine the constitutionality of affirmative action.

The approach, he said, "has developed solely through judicial and executive branch decisions."

Describing affirmative action as the "son of separate but equal," Hatch restated his belief that the concept "represents a significant retreat" from the civil rights efforts of the 1950s and 1960s.

He also referred his audience to his 120-page statement of last Sept. 3 in which he described affirmative action as "an assault upon America, conceived in lies and fostered with an irresponsibility so extreme as to verge upon the malign."

"The thing that bothers me," he said yesterday, "is that so many people in our society are terried to even discuss this issue for fear of being called a racist. . . . We want to create some dialogue here."

Two of yesterday's four witnesses, all legal experts, echoed many of Hatch's sentiments and urged that the government be taken out of what they consider the racial perference business and made "colorblind."

Duke University professor William Van Alstyne, who said that he had been a civil rights activist during the 1960s and still supports the movement, urged Congress to enact a law "forbidding any form of racial discrimination by the government of the United States."

Systematic "racial skewing" in schools and jobs is "stamping [minorities and women] with an empirical badge of inferiority" because it is perceived that they are held to a lower standard of performance, Van Alstyne argued. The approach also has promoted a "competition for racial spoils" among various groups, he said.

Such "Balkanization" of ethnic groups, if allowed to proceed very far, will lead to problems here similar to those currently wracking Lebanon and Ireland, "duplicated, triplicated to the tenth exponential power," said lawyer Morris Abram of New York, a human rights activist who has won a number of key civil rights cases over four decades.

"A color-conscious interpretation of the Constitution," he said, "provides a loaded weapon for those who would use it for some other urgent purpose."

Two other witnesses argued in favor of continuing some form of racial perference and stated that the Constitution permits racially based government action in furtherance of society's goals.

Much of the concern about increasing ethnic compeition "results from a failure to recognize that we are talking about black and white," said Robert Sedler, a law professor at Wayne State University. "We are basically talking about overcoming past injustice directed at blacks" and this has been extended to certain other groups perceived as nonwhite. . . . If we focus on this, I don't think there's a danger of a racial spoils system."

Martin Kilson, a professor at Harvard and the only black witness yesterday, agreed that there are stigmas associated with certain affirmative action procedures.

"But stigmas are relative," he said, suggesting that new stigmas that go with advancement are easier for many women and blacks to tolerate then the old stigmas of classic discrimination. He noted that other groups had managed to live with such stigmas, and cited the example of "Italian contractors in Massachusetts who, everybody knows," win lucrative contracts because of political patronage. "They are willing to accept the stigma."

"If you are to impose a worst-case scenario on us," Kilson told Hatch, "if affirmative action is going down the drain, then give us a Marshall Plan for the marginal working poor and those below the poverty line. . . . I have no doubt you're going to shave off something, from that smile on your face. But don't shave off too much."

"Never interpret my smiles," Hatch said with a faint smile.

The Senate Judiciary subcommittee on the Constitution plans eight to 10 hearings on the subject this year. Hatch has already introduced a constitutional amendment that would bar federal and state governments from making any distinctions based on race, color or national origin.